1. Field of the Invention
The present invention relates to a vehicle antenna and in particular to the use of electroconductive ceramic thermoplastic, thermoset and ultraviolet radiation cured paints as antenna elements or connectors in an antenna system for a radio or other transmitting/receiving device.
2. Technical Considerations
In the past the traditional motor vehicle antenna for receiving and transmitting electromagnetic signals was a mast or whip-type antenna. Recently, there has been a trend towards incorporating the antenna into the vehicle structure. For example, U.S. Pat. Nos. 4,992,801 to Saito, et al.; 5,083,134 to Saitou, et al.; and 5,416,491 to Nishikawa, et al. disclose antennas wherein electrically conductive elements are printed on the surface of a glass window. U.S. Pat. Nos. 4,768,037 and 4,849,766 to Inaba, et al.; 5,355,144 to Walton, et al.; 5,528,314 to Nagy, et al. and 5,670,966 to Dishart, et al. disclose a transparent electroconductive coating over a substantial portion of a window, and in particular a vehicle windshield to form an antenna.
Electroconductive ceramic paint of the type generally used to form heating lines or antenna elements on the window surfaces of vehicles, includes silver particles, glass frit, flow modifying agents, pigments and an infrared radiation dried carrier (hereinafter referred to as "electroconductive ceramic IR paint"). Using this type of material, the antenna pattern is screen printed on the surface of a glass ply using techniques well known in the art and heated in an oven or furnace to dry the ceramic paint. Additional or prolonged heating is required to cure the paint and bond it to the glass. This same type of material may be used to provide an electrical connection to a transparent coating forming an antenna. Although the use of electroconductive ceramic IR paints provides acceptable results, one shortcoming of using this type of ceramic paint is that it remains wet for an extended period of time, i.e. generally until it is dried by an oven. As a result, processing time is lengthened. Furthermore, if additional paint patterns are to be screened over the previously coated surface, the first paint coating must be dried before the second paint coating is applied.
It would be advantageous to provide an antenna system that could easily be applied and processed without requiring additional processing operations after applying the antenna or connection material.